Purpose: The aim of this study was to evaluate the efficacy and toxicities of induction chronomodulated chemotherapy in comparison with conventional induction chemotherapy for nasopharyngeal carcinoma (NPC).Patients and Methods: Between 2003 and 2004, 60 patients with pathologically confirmed NPC were included and randomly assigned to two groups. Patients in the chronomodulated chemotherapy group (n = 30, CC group) received cisplatin at 80 mg/m2 through intravenous infusion from 10:00 to 22:00 and 5-fluorouracil (5-FU) at 1000 mg/m2 plus citrovorum factor at 200 mg/m2 from 22:00 to 10:00 each day for 3 days. Patients in the routine chemotherapy group (n = 30, RC group) received cisplatin infusion within 1 h and 5-FU infusion for about 24 h. The dose in the RC group was the same as that in the CC group. The total irradiation dose in each group was 70 Gy for the whole nasopharynx.Results: One month after induction chemotherapy, the overall response rate was 96.7% in the CC group versus 73.3% in the RC group (P = 0.011). By the end of the 10-year follow-up, 11 patients (36.7%) in the CC group had experienced local recurrence versus 11 patients (36.7%) in the RC group (P > 0.999). The overall survival rates at 1, 5, and 10 years were 96.7%, 53.3%, and 43.3%, respectively, in the CC group, and 96.7%, 43.3%, and 33.3%, respectively, in the RC group (P = 0.346). During induction chemotherapy, the incidence rates of leukocytopenia (43.3% vs. 80%, P = 0.003), thrombocytopenia (26.7% vs. 56.7%, P = 0.018), and nausea/vomiting (40% vs. 66.7%, P = 0.038) were significantly lower in the CC group than in the RC group. The incidence of radiation-induced complications was similar in these two groups.Conclusion: Compared with conventional chemotherapy, induction chrono-chemotherapy seemed to reduce chemotherapy-related toxicities and improve average local relapse time in patients treated with combined chemoradiotherapy for NPC.

Nasopharyngeal carcinoma (NPC) is a distinct geographical disease with a high incidence in South China and South Asia.[1] Most patients present with stage III or IV disease when they are first diagnosed with NPC. Although NPC often responds well to radiotherapy (RT), the outcomes of patients with advanced stage disease have been unsatisfactory because of the high local recurrence and distant metastasis.[2] Chronomodulated chemotherapy (CC) is administered at a dosage and regimen based on circadian variation. The rate-limiting enzyme involved in 5-fluorouracil (5-FU) catabolism is dihydropyrimidine dehydrogenase (DPD). DPD is responsible for more than 80% of 5-FU elimination. Therefore, inhibition of 5-FU degradation would increase the concentration and hence improve the bioavailability of 5-FU.[3] Jacobs et al.[4] showed that the peak of activity of DPD enzyme occurred at 4:00 p.m. and the trough activity at 4:00 a.m. Glutathione (GSH) is a tripeptide involved in platinum complex detoxification. Zeng et al.[5] found that the peak GSH concentration occurred around 12:40. These findings implied that the chronomodulated therapeutic schedule of 5-FU and platinum could probably apply to Chinese NPC patients. Xian et al.[6] revealed the mechanism of circadian rhythm in DNA synthesis in NPC cells and suggested its potential in the clinical application of CC for patients with NPC. In a retrospective study, Ling et al.[7] demonstrated a significant improvement in the short-term efficacy of induction CC and RT in NPC treatment compared with chemotherapy alone. Lin et al.[8] demonstrated that CC significantly reduced stomatitis in NPC patients during RT; however, no significant reduction in hematologic toxicity was reported. Hai-Xia et al.[9] demonstrated that oxaliplatin and 5-FU combined with CC, compared to conventional chemotherapy, could significantly reduce the toxicity of oxaliplatin and 5-FU without jeopardizing the long-term survival of patients. Fang-Yang et al.[10] proved that concurrent chemo-RT with late course three-dimensional conformal RT had a satisfying efficacy for treating advanced NPC, and the adverse reaction was tolerable. To further evaluate the efficacy and toxicities of induction CC in NPC, we performed this Phase II prospective randomized study.

> Patients and Methods

Subject recruitment and study design

The protocol was reviewed and approved by the ethics committee, and the study was conducted in accordance with the principles of the Declaration of Helsinki. Written informed consent was obtained before randomization. All 60 patients were stratified into the induction CC group or the induction routine chemotherapy group (RC group). After two cycles of CC or RC, patients underwent RT. Toxicities during and after the treatment were recorded and scored based on common terminology criteria for adverse events (CTC-AEs) version 3.0. Treatment responses were obtained based on magnetic resonance imaging (MRI) scans taken 1 month after the treatment. All patients were followed until October 2014.

Inclusion and exclusion criteria

Patients were eligible for this study if they met the following entry criteria: (1) histologically proven NPC without evidence of systemic metastasis (M0); (2) age younger than 70 years but older than 17 years; and (3) Karnofsky score (KPS) ≥60. They were required to have adequate hematologic, hepatic, and renal function. The exclusion criteria included (1) age younger than 18 years; (2) pregnancy; (3) insufficient hepatic or renal function and history of malignancy; (4) prior treatment for NPC; or (5) refusal to participate in this study.

Pretreatment evaluation

The pretreatment evaluation included a medical history and physical examination, baseline hematologic and biochemical profiles, and electrocardiography. All patients underwent fiberoptic endoscopy, biopsy, and MRI scanning of the nasopharynx. The metastatic workup included chest radiography, live ultrasonography, and bone scintigraphy. All patients were referred for dental examination before RT.

Treatment

Patients in the CC group received cisplatin at 80 mg/m2 through infusion from 10:00-22:00 and 5-FU at 1000 mg/m2 plus citrovorum factor (CF) at 200 mg/m2 from 22:00 to 10:00 each day for 3 days. Patients in the RC group finished the cisplatin infusion within 1 h and 5-FU infusion over about 6 h. The dose in the RC group was the same as that in the CC group. Infusion started at 10:00, and DPP and CF infusions were given at a normal speed each day for 3 days. 5-FU was continuously administered for 3 days. One cycle was defined as 14 days, and the chemotherapy was repeated for two cycles.

RT was started within 2 weeks after the completion of induction chemotherapy. Irradiation fields were decided according to the range of tumor invasion. Irradiation was given to the composite facio-cervical field and anterior cervical tangential field at a dose of dose of tumor 40 Gy in 4 weeks, followed by irradiation to cone down per-auricular field plus anterior tangential field and ß-beam irradiation. The total irradiation dose to the nasopharyngeal area was 70 Gy in 7 weeks, 60–70 Gy in 6–7 weeks to the region of cervical nodal metastasis, and 50 Gy in 5 weeks for prophylactic irradiation to the neck.

Toxicities and treatment response

The primary endpoints were toxicities and the short-term effects related to treatment. The secondary endpoint was the long-term effects. The toxicities were scored based on the CTC-AE 3.0. Recorded toxicities included leukocytopenia, anemia, thrombocytopenia, nausea, vomiting, blood transaminase alteration, blood/urea nitrogen alteration, difficulty in opening mouth, xerostomia, radiation-induced otitis media, and fibrosis.

Short-term response was evaluated according to the World Health Organization response criteria 1 month after induction chemotherapy and 3 months after RT, including complete response (CR), which was defined as the absence of clinical or radiographic evidence of residual disease; partial response (PR), which was defined as tumor shrinkage >50% of the sum of the longest diameters of all measurable lesions with no progression of assessable disease and no new lesions, stable disease, which was defined as a change in tumor volume of no more than 25% of the sum of the longest diameters of all measurable lesions with no new lesions; and progressive disease, which was defined as an increase in tumor volume or the appearance of new lesions by more than 25%.

Overall survival (OS) was defined as the duration from the initiation of treatment to death of patients from any cause. Local recurrence-free survival (LRFS) was defined as the duration from the end of the treatment to the local recurrence of the disease. Distant metastasis-free survival (DMFS) was defined as the end from the initiation of treatment to the distant metastasis of the disease.

Follow-up

Patients were followed up every 3 months for the first 1–2 years after the treatment, every 4–6 months for year 3 to year 5 after the treatment, and every 6–12 months for 5 years after the treatment. Follow-up tests included fiberoptic nasopharyngoscope, nasopharyngeal and neck computed tomography or MRI, routine laboratory tests, hepatic and renal function tests, electrolyte tests, chest X-ray tests, and abdominal ultrasound test. Serum EB-IgA, VCA-IgA, and bone scanning were tested every 6–12 months. Outpatient follow-up was the main approach, and telephone follow-up was considered auxiliary. By October 2014, all patients underwent median follow-up of 130.5 months (range, 123–138 months).

Statistical analysis

SPSS 19 was used for statistical analysis. The Kaplan–Meier method was used in the estimation of OS, Local recurrence-free survival, and DMFS. Log-Rank test was used to comparing about the differences in survival between the groups. Chi-square test was used for the treatment response and toxicity evaluation. All statistical tests were two sided, and P < 0.05 was considered statistically significant.

> Results

Patients

From April 2003 to July 2004, 60 eligible patients were included in this study. Baseline patient characteristics are listed in [Table 1]. There were no significant differences between the two groups in terms of any of these characteristics.

The treatment responses in each group are shown in [Table 2]. One month after induction chemotherapy, the overall response rate was 96.7% in the CC group versus 73.3% in the RC group (P = 0.011). The response rate was significantly higher in the CC group than in the RC group. Three months after RT, the overall response rate was 100% in the CC group versus 96.7% in the RC group.

The chemotherapy-related toxicity was summarized in [Table 3]. The incidence rates of leukocytopenia, thrombocytopenia, nausea, and vomiting were all significantly lower in the CC group than in the RC group.

Long-term complications of RT are summarized in [Table 4]. The most frequent serious long-term radiation-induced complication has been difficulty opening one's mouth (50% in the CC group vs. 46.7% in the RC group, P = 0.796), radiation xerostomia (73.3% in the CC group vs. 70% in the RC group, P = 0.774), radiation otitis media (23.3% in the CC group vs. 30% in the RC group, P = 0.559), and fibrosis (63.3% in the CC group vs. 56.7% in the RC group, P = 0.598). No radiation cranial nerve injury or radiation osteomyelitis of jaw was observed in either group. There also was no significant difference between the two groups in terms of the incidence of the long-term radiation-induced complications.

The nasopharyngeal control rate and the nodal control rate are summarized in [Table 5]. The nasopharyngeal control rates were 90.0%, 73.3%, and 53.3% in the CC group at years 1, 3, and 6, respectively, while the nasopharyngeal control rates were 86.7%, 66.7%, and 43.3% in the RC group, respectively. The nodal control rates were 93.3%, 73.3%, and 50.0% in the CC group at years 1, 3, and 6 respectively, while the nodal control rates were 83.3%, 63.3%, and 43.3% in the RC group, respectively. In the CC group, 11 patients had recurrence, including 6 patients with nasopharynx recurrence, 3 patients with cervical lymph node recurrence, and 2 patients with both nasopharynx and cervical lymph node recurrence. In comparison, there were 11 cases of recurrent cancer in the RC group, including 5 cases in the nasopharynx, 5 cases in the cervical lymph node, and 1 case in both the nasopharynx and cervical lymph node. The local recurrence rates in the CC group and the RC group were 36.7% and 36.7%, respectively. There was no statistically significant difference (P > 0.999). In the CC group, 7 patients had distant metastatic diseases, while 10 patients had distant metastasis in the RC group. The distant metastatic rates in the CC group and RC group were 23.3% and 30%, respectively (P = 0.390). Two cases experienced both recurrence and metastasis in the CC group, and 1 case experienced both recurrence and metastasis in the RC group. There was a statistically significant difference in the average local relapse time between the CC group and RC group (22.6 months vs. 11.9 months, t = 2.261, P = 0.034). The local relapse rates in the CC group and RC group were 36.7% and 36.7%, respectively. There was no statistically significant difference (P = 1). In the CC group, 7 patients had distant metastatic disease, while 10 patients showed distant metastasis in the RC group. There was no statistically significant difference between the CC group and RC group of the average times of metastasis (12.4 months vs. 15.5 months, t = 0.553, P = 0.588). The distant metastatic rates in the CC group and RC group were 23.3% and 30%, respectively (P = 0.390).

The median survival time was 72 months in the CC group versus 55 months in the RC group, and the OS rates in the CC group and RC group at years 1, 5, and 10 were 96.7%, 53.3%, and 43.3% and 96.7%, 43.3%, and 33.3%, respectively [P = 0.829; [Figure 1]. The corresponding LRFS in these two groups at years 1, 5, and 10 were 96.7%, 80%, and 76.7% and 96.7%, 70%, and 70%, respectively [P = 0.941; [Figure 2]. The corresponding DMFS in these two groups at years 1, 5, and 10 were 90%, 83%, and 83% and then 90%, 73.3%, and 73.3%, respectively [P = 0.929; [Figure 3]. There were no significant differences between the two groups in terms of OS, LRFS, and DMFS.

Figure 1: The overall survival in chronomodulated chemotherapy group and routine chemotherapy group

Circadian rhythm exerts influence on cellular proliferation cycle and apoptosis, neurological secretion and immunity, which is closely associated with the development, progression, treatment, and prognosis of malignancy. As an optimized treatment regimen based on the circadian rhythm of the human body and the circadian growth of tumor cells, chronomodulated therapy is considered to have better efficacy and less adverse effects than RC. According to this theory, 5-FU delivery was scheduled from 22:00 to10:00 every day for 3 days, and DDP infusion was given from 10:00 to 22:00 every day for 3 days. CF was administered simultaneously with 5-FU to enhance its anticancer activity. Significant differences in CR and PR (P = 0.011) were observed between the CC group and RC group as well as significant differences in the incidence of leukocytopenia and thrombocytopenia (P < 0.05). Gastrointestinal adverse reactions included nausea and vomiting, usually at Grade I–II. The results showed that CC could achieve better efficacy with lower toxicity rates compared to RC.

Induction chemotherapy can reduce tumor burden, alleviate symptoms of headache and blood in mucus rapidly, inhibit, and kill subclinical focal role. Therefore, patients with a high tumor load, reduced lymph node capacity, and a high tendency of metastasis are suitable for induction chemotherapy. Neoadjuvant chemotherapy can effectively gain 5.13% more absolute survival after 3 years and reduce the distant metastasis rate.[11],[12] However, in previous research, cisplatin plus 5-FU (PF) represented the main induction chemotherapy in NPC, which led to a remission rate between 75% and 93% (CR and PR) among newly diagnosed patients. Cisplatin plus 5-FU CC plus concurrent intensity-modulated RT for NPC could improve therapeutic effects with better tolerance of side effects.[13] The plasma half-life of 5-FU is about 10–20 min. In human and other mammals, the serum concentration of 5-FU showed an obvious circadian change while the drug was given at a constant infusion speed. The drug is, therefore, time dependent and dose dependent.[14] The secretion of DPD, a metabolic rate-limiting enzyme of 5-FU, had a clear circadian rhythm. In both healthy controls and cancer patients, the activity of DPD increased by 50% during the period from early morning to 10:00 a.m. to higher levels than at any other period of the day.[14] CF could enhance the anticancer ability of 5-FU. GSH could protect cells against oxidative damage and participate in the detoxification process of cell components. It could reverse the cytotoxicity of platinum drugs without reducing their efficacy. The same individual often has various levels of GSH secretion. The secretion of GSH during the day could be 1–5 times different compared to that at night, and the peak level of GSH secretion occurs in the afternoon. According to the circadian rhythm, continuous administration of the platinum drugs from 10:00 to 22:00 (for 12 h) could maximally lower the toxicity of DDP.[14] Chronobiological theory was proposed by Morris [15] who demonstrated that the circadian rhythm of humans originated from the molecular clock of suprachiasmatic nucleus, which is usually regulated by light. While melatonin secreted at night could maintain the internal rhythm of the body, during CC, the regimen with a 40% dose increase could lead to better efficacy and improve tolerance. Chronomodulated administration based on the rhythm of the body would generate better efficacy, lower toxicity rates, and improve quality of life. The incidence rates of leukocytopenia, thrombocytopenia, nausea, vomiting, radiation-related oral mucositis, and radiodermatitis were significantly lower in the CC group than in the RC group. CC might adjust the biological rhythms to increase efficacy and lower toxicity of the treatment.

The reported CR rate after induction chemotherapy for NPC varies (14%–38%).[16] Previous studies have reported that induction chemotherapy combined with RT has a higher rate of CR. Lin et al. reported that two cycles of induction chemotherapy combined with RT for NPC led to a significantly higher CR rate (95.2%) in their sinusoidal chronomodulated infusion group. High CR rates were achieved after RT in both groups of our study (100% in the CC group vs. 73.4% in the RC group). In our study, the 96.7% response rate and 23.3% CR of induction CC are superior to other reported cisplatin-based regimens.[17]

Frikha et al.[18] also reported that TPF chemotherapy regimens including cisplatin plus 5-FU could improve the local control rate among advanced stage T patients, despite the failure to improve OS or to reduce distant metastasis. Currently, TPF induction chemotherapy combined with concurrent chemo-RT and platinum drugs has become an efficient and safe standard treatment for NPC. Neoadjuvant TPF followed by concurrent chemoradiation was well tolerated and produced encouraging outcomes in locally advanced NPC.[19] The most common severe (Grade 3/4) hematologic and nonhematologic AEs were neutropenia (55.2%) and nausea/vomiting (19.8%).[20] Jun-Chang et al.[21] reported that TPF CC achieved 83.9% efficacy among patients with advanced stage of head and neck squamous cell carcinoma, while the incidence of Grade 3–4 leukopenia was 22.6%. Previous studies on TPF induction chemotherapy achieved ~70% efficacy and a 76.9% incidence of Grade 3–4 neutropenia, among which 5%–12% of patients had febrile neutropenia. TPF induction chemotherapy can increase short-term efficacy, but adding a chemotherapy drug also brings additional toxicity. Currently, sequential induction concurrent schedules have been widely explored in several Phase II trials and given favorable outcomes in NPC. Therefore, we concluded that CC could improve the efficacy of treatment while also decreasing the AEs.

In our study, at the end of the follow-up, 7 patients (23.3%) in the CC group had distant metastatic diseases, while 10 patients (30%) in the RC group had distant metastatic diseases (P = 0.390). The metastatic rate in the CC group was lower than that in the RC group, but this difference failed to achieve statistical significance. Thus, this slight difference failed to translate into survival benefit.[22]

> Conclusion

The short-term efficacy of induction CC (DDP + 5-FU/CF) was superior to that of RC. It could prolong the time before cancer recurrence, reduce the metastatic rate, and decrease adverse effects including leukocytopenia, thrombocytopenia, and nausea/vomiting. However, no significant long-term response was achieved. These findings may be applied to a broader range of patients who want to improve their survival rates and local control rates. These results are yet to be verified in clinical trials on a larger scale.

Acknowledgments

We would like to thank Prof. Li-Jian Xian and Lin Guo of Sun Yat-sen University Cancer Center for their assistance and guidance.